This invention relates generally to turbine engines, such as gas turbines and steam turbines, and more particularly to increasing the power density and/or efficiency of turbine engines.
Turbine engines have long been used for a variety of purposes, including power generation and aircraft and marine propulsion. Briefly, a gas turbine engine includes a compressor, which provides pressurized air to a combustor, wherein it is mixed with fuel and ignited for generating hot combustion gases. These gases are expanded in a turbine that extracts energy therefrom for powering the compressor and providing useful work. A steam turbine includes a turbine that is driven by the expansion of superheated steam, which is produced by a boiler or the like.
Various efforts have been used to enhance the efficiency and power output of these engines. For example, turbine reheat involves heating the gas or steam as it expands through the turbine to increase the turbine work output. The current practice for implementing reheat typically involves the injection of fuel, steam or any reheated working fluid at different stages. However, this practice requires use of generally massive and expensive auxiliary equipment such as valves, pumps, piping, etc.
Another technique for increasing efficiency in gas turbines is compressor intercooling, which involves cooling air between stages in the compressor at a constant pressure. This reduces the work needed to achieve compression because a cooler gas is more easily compressed. Like turbine reheat, compressor intercooling typically requires the addition of massive and expensive auxiliary equipment.
Accordingly, there is a need for a more compact and less expensive approach to increasing turbine engine power density and/or efficiency.